Here we describe an experimental system to determine the contribution that rapid intracellular proteolytic degradation makes to the efficiency of antigen presentation of viral proteins. In essence, our plan is to provide a mechanism whereby inherently stable viral proteins are retargeted for rapid proteolytic degradation. As a result, once immunologically inert viral proteins can be presented as their derivative peptide fragments on the surface of the cell in position for direct contact with the immune system. We will test the efficiency of antigen presentation in living cells or from the cross-presentation of antigens originating from apoptotic cells. In either case, we will employ an animal model to monitor the expansion of immune cells that preferentially target specific viral antigens.